Blocking queries responding on the coordinate endpoint, even when there is no change in the response

#### Overview of the Issue

I have a single node test setup and when request a blocking query on `/v1/coordinate/nodes`, it seems to respond roughly every 5-10 seconds even though the payload/response is exactly the same.

### Consul info for both Client and Server

Client info
1.4.0, 1.3.0 and 1.2.* at least

### Operating system and Environment details

All versions using the official docker image to run.